While heavy duty bumper systems have been built which are capable of meeting the above noted collision impact requirements, they have normally been relatively complicated of design and therefore costly to manufacture as well as being heavier than is to be desired.
The present bumper system is a companion to the one shown in my application Ser. No. 528,403 "Energy Absorbing Vehicle Bumper" filed Sept. 1, 1983, now U.S. Pat. No. 4,509,782. It has been found that by using a relatively rigid, though deflectable, hollow core element formed of a high strength plastic in place of a resilient foam core material several advantages inhere. First, by utilizing a unique core element design the bumper system can absorb higher impact loads before experiencing damage to system components. More specifically, the present bumper system can absorb higher impact loads than my earlier system before breaking or rupturing the energy absorbing core element. Next, the uniquely configured, hollow core element has further reduced the weight of the bumper system as well as simplifying its construction.
In addition, the following patents are illustrative of bumper systems which have been designed to perform in environments similar to that of the subject invention:
U.S. Pat. No. 3,897,095 "Resilient Bumper Assembly"--Glance et al
U.S. Pat. No. 3,902,748 "Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
U.S. Pat. No. 3,989,292 "Semi-Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
U.S. Pat. No. 4,103,951 "Semi-Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
None of the foregoing structures disclose or suggest applicant's unique bumper system.